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In this study, cooling characterization of a conceptual Joule-Thomson cryogenic cooler operating with argon or nitrogen gases as coolant is studied by using numerical approach. Because of geometric complexities, a one dimensional model is used to study the thermo-fluidic behavior of the system. Heat transfer correlations used in the previous investigations are used while the thermodynamic properties of selected real gases are calculated by utilizing an inhouse code based on formulations presented in the literature. In most of the previous studies, the same friction factor formulation is used in pressure loss calculations. In this study, pressure drop is calculated through a different approach. The major distinction of present study is related to pressure drop calculations. Since the model is one dimensional, finite difference method is applied to solve differential form of governing equations. Numerical results are validated with the results published in the literature and satisfactory agreement is obtained. © 2016, International Institute of Refrigeration. All rights reserved., Asociatia Frigotehnistilor Si Criogenistilor Din Romania (AFCR);Criomec SA;I.C.S.I. Rm.Valcea

This study aimed to describe the effect of initial antifungal therapy on patient mortality and to detail the current distribution and resistance patterns of Candida spp. among patients with candidaemia. A prospective observational study was performed among consecutive patients with candidaemia from 10 Turkish medical centres between January 2015 and November 2018. The primary outcome was 10-day mortality. Species were identified using MALDI-TOF/MS. A total of 342 patients with candidaemia were included, of which 175 (51.2%) were male and 68 (19.9%) were aged <18 years. The most common species were Candida albicans (47.4%), Candida parapsilosis (26.6%), Candida tropicalis (9.6%) and Candida glabrata (7.6%). Among all Candida spp., the 10-day case fatality rate (CFR) was 32.2%. The CFR was highest in patients with C. albicans (57.3%) and lowest in patients with C. parapsilosis (21.8%). The resistance rate to fluconazole was 13% in C. parapsilosis, with no significant effect on mortality. No resistance to echinocandins was detected. In the multivariate analysis, being in the ICU [OR = 2.1 (95% CI 1.32–3.57); P = 0.002], renal failure [OR = 2.4 (1.41–3.97); P = 0.001], total parenteral nutrition [OR = 2 (1.22–3.47); P = 0.006], C. albicans infection [OR = 1.7 (1.06–2.82); P = 0.027] and echinocandin as primary agent [OR = 0.6 (0.36–0.99); P = 0.047] were significantly associated with mortality. Candidaemia is a deadly infection. Fluconazole resistance is emerging, although it was not significantly related to mortality. Using an echinocandin as the primary agent could be life-saving., NA

Escherichia coli ST131 is a cause for global concern because of its high multidrug resistance and several virulence factors. In this study, the contribution of acrAB-TolC efflux system of E. coli ST131 to fluoroquinolone resistance was evaluated. A total of nonrepetitive 111 ciprofloxacin-resistant E. coli isolates were included in the study. Multilocus sequence typing was used for genotyping. Expressions of acrA, acrB, and TolC efflux pump genes were measured by RT-PCR. Mutations in marA, gyrA, parC, and aac(6)-lb-cr positivity were studied by Sanger sequencing. Sixty-four (57.7%) of the isolates were classified as ST131, and 52 (81.3%) of the ST131 isolates belonged to H30-Rx subclone. In ST131, CTX-M 15 positivity (73%) and aac(6)-lb-cr carriage (75%) were significantly higher than those in non-ST131 (12.8% and 51%, respectively) (P<0.05). The ampicillin-sulbactam (83%) resistance was higher, and gentamicin resistance (20%) was lower in ST131 than that in non-ST131 (64% and 55%, respectively) (P=0.001 and P=0.0002). Numbers of the isolates with MDR or XDR profiles did not differ in both groups. Multiple in-dels (up to 16) were recorded in all quinolone-resistant isolates. However, marA gene was more overexpressed in ST131 compared to that in non-ST131 (median 5.98 vs. 3.99; P=0.0007). Belonging to H30-Rx subclone, isolation site, ciprofloxacin MIC values did not correlate with efflux pump expressions. In conclusion, the marA regulatory gene of AcrAB-TolC efflux pump system has a significant impact on quinolone resistance and progression to MDR profile in ST131 clone. Efflux pump inhibitors might be alternative drugs for the treatment of infections caused by E. coli ST131 if used synergistically in combination with antibiotics., NA

We investigate the shock dynamics of liquid flows containing small gas bubbles with numerical simulations based on a continuum bubbly flow model. Particular attention is devoted to the effects of distributed bubble sizes and gas-phase nonlinearity on shock dynamics. Ensemble-averaged conservation laws for polydisperse bubbly flows are closed with a Rayleigh–Plesset-type model for single bubble dynamics. Numerical simulations of one-dimensional shock propagation reveal that phase cancellations in the oscillations of different-sized bubbles can lead to an apparent damping of the averaged shock dynamics. Experimentally, we study the propagation of waves in a deformable tube filled with a bubbly liquid. The model is extended to quasi-one-dimensional cases. This leads to steady shock relations that account for the compressibility associated with tube deformation, bubbles and host liquid. A comparison between the theory and the water-hammer experiments suggests that the gas-phase nonlinearity plays an essential role in the propagation of shocks.

In this study the FM fields produced by high power 3-phase transmission lines are investigated. The dependence of the magnetic field with respect to vertical and horizontal distances from the transmission lines are illustrated and the minimum distance from the lines for human safety is specified according to ICNIRP standards. In addition a quasi-static examination to the magnetic shielding of several enclosures are performed. In the analysis, the integral form of Maxwell's equations with boundary conditions are used to derive the shielding effectiveness (SE) equations. An experiment is carried out to verify the validity of the theory developed for magnetic fields of transmission lines and the SE provided by the building. An excellent agreement is obtained for experimental and theoretical results., Presented at Annual International Conference of the IEEE Engineering in Medicine and Biology Society (23rd) held in Istanbul, Turkey on 25-28 Oct 2001. See also ADM001351 for entire conference on CD-ROM. The original document contains color images.